Diagnosis and treatment of primary aldosteronism

Adrenal Vein Sampling in Primary Aldosteronism: A Pictorial Essay for Optimal Left-Side Sampling

Primary aldosteronism (PA) is a curable cause of hypertension. Recent studies have revealed that the actual prevalence of PA is higher than previously recognized. Adrenal vein sampling (AVS) is an essential diagnostic procedure for revealing the cause of PA and determining the treatment plan. The success of AVS is confirmed by comparing cortisol levels between the samples from each adrenal vein and peripheral vein. The failure rate of the procedure is reported to be high in the right adrenal vein, which is directly connected to the inferior vena cava, while that in the left adrenal vein is relatively low; however, this has rarely been reported. In this review, we introduce and analyze cases of failure in left adrenal vein sampling.

Taiwan mini-frontier of primary aldosteronism: Updating detection and diagnosis

BACKGROUND

To update information about the internationally accepted standards and clinical recommendations for the detection and diagnosis of primary aldosteronism (PA).

METHODS

The Taiwan Society of Aldosteronism (TSA) Task Force reviewed the latest literature and reached a consensus after group meetings. The nine critical issues were recognized to provide updated information and internationally acceptable protocols.

RESULTS

When screening for PA by using the plasma aldosterone concentration (PAC) to plasma renin activity (PRA) ratio (ARR), withdrawal or adjustment of antihypertensive medication is not always necessary on the first patient visit. Hypokalemia should be corrected before ARR screening. In spontaneous hypokalemia, plasma renin below detection levels, and PAC higher than 20 ng/dL (550 pmol/L), further confirmatory testing is unnecessary for PA diagnosis. Direct renin concentration (DRC) could be used for PA diagnosis if PRA is unavailable. Although additional confirmatory tests are suggested, the result of a single test is still reliable. For patient safety, discontinuation or adjustment of antihypertensive medications is indicated before adrenal venous sampling (AVS). ACTH could be beneficial for successful adrenal vein cannulation but is not necessary for determining lateralization in AVS. Simultaneous technique is preferred for AVS. Adrenal NP-59 scintigraphy integrated with SPECT/CT could guide PA management.

CONCLUSION

With introduction of these new concepts to the clinicians, we expect better identification, management and treatment of PA patients.

10 good reasons why adrenal vein sampling is the preferred method for referring primary aldosteronism patients for adrenalectomy

: Nowadays most patients diagnosed with surgically curable primary aldosteronism have small or micro aldosterone-producing adenoma or unilateral micronodular hyperplasia, which are undetectable with available imaging technologies. Therefore, a negative imaging test by no means excludes unilateral primary aldosteronism. Moreover, about 10% of the subjects above the age of 35 years have nonfunctioning adrenal tumors, regardless of being hypertensive or not, with a prevalence that raises with aging. Hence, the finding of an adrenal mass at imaging does not reliably detect the culprit of primary aldosteronism. On the other hand, when primary aldosteronism patients are selected for adrenalectomy on the basis of demonstration of lateralized aldosterone excess at adrenal vein sampling (AVS), close to 100% are biochemically cured from the hyperaldosteronism, about 45% are cured of arterial hypertension and an additional 52% are markedly improved in terms of blood pressure control. By contrast, patients referred for surgery based on imaging alone often fail to reach these successful outcomes, indicating that surgery was unnecessary or, even worse, performed on the wrong side. For these reasons, and because of the lack of accurate and widely available alternative methods, all current guidelines recommend that AVS be offered to all primary aldosteronism patients with only few exceptions, mainly in patients unable or unwilling to undergo surgery and those with germ-line mutations causing familial primary aldosteronism. The main argument against systematic use of AVS entails its suboptimal performance, partly justified by its intrinsic technical difficulty, and its limited availability. This led to propose skipping AVS strategies for predicting surgically curable primary aldosteronism, but success has been inconsistent. The most urgent standing issue is, therefore, not to find loopholes to avoid AVS, but rather to improve its use, which means improving the rate of AVS success, through formal training of interventionists, selection of appropriate cutoffs and exploitation of a standardized procedure.

A preliminary study of the effect of a high-salt diet on transcriptome dynamics in rat hypothalamic forebrain and brainstem cardiovascular control centers

BACKGROUND

High dietary salt intake is strongly correlated with cardiovascular (CV) diseases and it is regarded as a major risk factor associated with the pathogenesis of hypertension. The CV control centres in the brainstem (the nucleus tractus solitarii (NTS) and the rostral ventrolateral medulla (RVLM)) and hypothalamic forebrain (the subfornical organ, SFO; the supraoptic nucleus, SON and the paraventricular nucleus, PVN) have critical roles in regulating CV autonomic motor outflows, and thus maintaining blood pressure (BP). Growing evidence has implicated autonomic regulatory networks in salt-sensitive HPN (SSH), but the genetic basis remains to be delineated. We hypothesized that the development and/ or maintenance of SSH is reliant on the change in the expression of genes in brain regions controlling the CV system.

METHODOLOGY

We used RNA-Sequencing (RNA-Seq) to describe the differential expression of genes in SFO, SON, PVN, NTS and RVLM of rats being chronically fed with high-salt (HS) diet. Subsequently, a selection of putatively regulated genes was validated with quantitative reverse transcription polymerase chain reaction (qRT-PCR) in both Spontaneously Hypertensive rats (SHRs) and Wistar Kyoto (WKY) rats.

RESULTS

The findings enabled us to identify number of differentially expressed genes in SFO, SON, PVN, NTS and RVLM; that are either up-regulated in both strains of rats (SON- Caprin2, Sctr), down-regulated in both strains of rats (PVN- Orc, Gkap1), up-regulated only in SHRs (SFO- Apopt1, Lin52, AVP, OXT; SON- AVP, OXT; PVN- Caprin2, Sclt; RVLM- A4galt, Slc29a4, Cmc1) or down-regulated only in SHRs (SON- Ndufaf2, Kcnv1; PVN- Pi4k2a; NTS- Snrpd2l, Ankrd29, St6galnac6, Rnf157, Iglon5, Csrnp3, Rprd1a; RVLM- Ttr, Faim).

CONCLUSIONS

These findings demonstrated the adverse effects of HS diet on BP, which may be mediated via modulating the signaling systems in CV centers in the hypothalamic forebrain and brainstem.

Adrenal Venous Sampling: Where Do We Stand?

Adrenal venous sampling is the gold standard test to identify surgically curable primary aldosteronism, but it is markedly underused in clinical practice being perceived as a technically challenging and invasive procedure and, moreover, as difficult to interpret. This review provides updated information on current indications to adrenal venous sampling and how to perform and interpret adrenal venous sampling.

Update in adrenal venous sampling for primary aldosteronism

PURPOSE OF REVIEW

Current guidelines recommend adrenal venous sampling (AVS) to identify the surgically curable causes of hyperaldosteronism. In contrast with this recommendation, AVS remains markedly underutilized in clinical practice, which leads to deny curative adrenalectomy, to many patients with primary aldosteronism. The purpose of this review is to challenge the views that AVS is a technically challenging, invasive and risky procedure, which moreover, is difficult to interpret.

RECENT FINDINGS

Several studies, including a large international survey on how AVS is being performed and used at major referral centres worldwide the AVIS-1 Study - and a randomized clinical trial comparing and AVS and a computed tomography based strategy, will be examined.

SUMMARY

The results of these studies have sound implications for clinical practice in that they allow to define what to do and what not to do for proper performance and interpretation of AVS and avoidance of the main concern, for example the risk of adrenal vein rupture.

Analysis of postoperative biochemical values and clinical outcomes after adrenalectomy for primary aldosteronism

BACKGROUND

Primary aldosteronism causes hypertension and hypokalemia and is often surgically treatable. Diagnosis includes elevated plasma aldosterone, suppressed plasma renin activity, and elevated aldosterone renin ratio. Adrenalectomy improves hypertension and hypokalemia. Postoperative plasma aldosterone and plasma renin activity may be useful in documenting cure or failure.

METHOD

A retrospective analysis of patients who underwent adrenalectomy for primary aldosteronism from 2010 to 2016 was performed, analyzing preoperative and postoperative plasma aldosterone, plasma renin activity, hypertension, and hypokalemia. The utility of postoperative testing was assessed. Clinical cure was defined as improved hypertension control and resolution of potassium loss. Biochemical cure was defined as aldosterone renin ratio reduction to <23.6.

RESULTS

Forty-four patients were included; 20 had plasma aldosterone and plasma renin activity checked on postoperative day 1. In the study, 40/44 (91%) were clinically cured. All clinical failures had of biochemical failure at follow-up. Postoperative day 1aldosterone renin ratio <23.6 had PPV of 95% for clinical cure. Cured patients had mean plasma aldosterone drop of 33.1 ng/dL on postoperative day 1; noncured patient experienced 3.9 ng/dL increase. A cutoff of plasma aldosterone decrease of 10 ng/dL had high positive predictive value for clinical cure.

CONCLUSION

Changes in plasma aldosterone and plasma renin activity after adrenalectomy correlate with improved hypertension and hypokalemia. The biochemical impact of adrenalectomy manifests as early as postoperative day 1. We propose a plasma aldosterone decrease of 10 ng/dL as a criterion to predict clinical cure.

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Zusammenfassung. In diesem Mini-Review wird aufgezeigt, dass die Diagnostik der sekundären Hypertonie eigentlich eine relativ einfache Unternehmung ist. Neben einer umfassenden Anamnese sowie einer korrekt durchgeführten klinischen Untersuchung muss bei jeder Diagnosestellung einer arteriellen Hypertonie an die Möglichkeit einer sekundären Ursache gedacht werden. Oft ist es auch kostengünstiger, beim geringsten Verdacht direkt nach einer sekundären Ursache zu suchen, als durch langwierige Umstellungen der Therapie und damit auch Verunsicherung des Patienten die Diagnostik zu verzögern.

Primary Aldosteronism: Diagnosis and Management

Primary aldosteronism (PA) is an important and commonly unrecognized cause of secondary hypertension. Idiopathic hyperaldosteronism and aldosterone-producing adenomas account for more than 95% of PA and are characterized, respectively, by bilateral or unilateral involvement of the adrenal glands. When there is suspicion for the presence of PA, a plasma aldosterone to renin ratio should be obtained initially. Localization to determine adrenal gland involvement is done by imaging, with computerized tomography or magnetic resonance imaging. After imaging, adrenal vein sampling is done to establish treatment options. Patients with unilateral disease, who are good surgical candidates, are most appropriately managed with adrenalectomy. A biochemical cure is almost certain following adrenalectomy; however, only 30-50% of patients would show adequate blood pressure improvement. Patients with bilateral adrenal disease and those believed not to be surgical candidates are managed with mineralocorticoid antagonists.

The Management of Primary Aldosteronism: Case Detection, Diagnosis, and Treatment: An Endocrine Society Clinical Practice Guideline

OBJECTIVE

To develop clinical practice guidelines for the management of patients with primary aldosteronism.

PARTICIPANTS

The Task Force included a chair, selected by the Clinical Guidelines Subcommittee of the Endocrine Society, six additional experts, a methodologist, and a medical writer. The guideline was cosponsored by American Heart Association, American Association of Endocrine Surgeons, European Society of Endocrinology, European Society of Hypertension, International Association of Endocrine Surgeons, International Society of Endocrinology, International Society of Hypertension, Japan Endocrine Society, and The Japanese Society of Hypertension. The Task Force received no corporate funding or remuneration.

EVIDENCE

We searched for systematic reviews and primary studies to formulate the key treatment and prevention recommendations. We used the Grading of Recommendations, Assessment, Development, and Evaluation group criteria to describe both the quality of evidence and the strength of recommendations. We used "recommend" for strong recommendations and "suggest" for weak recommendations.

CONSENSUS PROCESS

We achieved consensus by collecting the best available evidence and conducting one group meeting, several conference calls, and multiple e-mail communications. With the help of a medical writer, the Endocrine Society's Clinical Guidelines Subcommittee, Clinical Affairs Core Committee, and Council successfully reviewed the drafts prepared by the Task Force. We placed the version approved by the Clinical Guidelines Subcommittee and Clinical Affairs Core Committee on the Endocrine Society's website for comments by members. At each stage of review, the Task Force received written comments and incorporated necessary changes.

CONCLUSIONS

For high-risk groups of hypertensive patients and those with hypokalemia, we recommend case detection of primary aldosteronism by determining the aldosterone-renin ratio under standard conditions and recommend that a commonly used confirmatory test should confirm/exclude the condition. We recommend that all patients with primary aldosteronism undergo adrenal computed tomography as the initial study in subtype testing and to exclude adrenocortical carcinoma. We recommend that an experienced radiologist should establish/exclude unilateral primary aldosteronism using bilateral adrenal venous sampling, and if confirmed, this should optimally be treated by laparoscopic adrenalectomy. We recommend that patients with bilateral adrenal hyperplasia or those unsuitable for surgery should be treated primarily with a mineralocorticoid receptor antagonist.

[Hypokalemia, a key clinical data for diagnosing primary hyperaldosteronism]

We report a case of a 37 year-old man with a long history of hypertension under treatment, who was admitted at our institution with intense fatigue and weakness of lower limbs. The laboratory results at Emergency Department showed severe hypokalemia. A study of secondary hypertension was carried out. With the initial suspicion of primary hyperaldosteronism, complete blood test was done including plasma renine activity, which was completely suppressed, and plasma aldosterone concentration, which resulted normal. Likewise, an abdomen CT was performed and revealed a left adrenal mass consistent of suprarrenal adenoma. Therefore, a salt loading suppression test was done with subsequent measure of plasmatic renine activity, which was still suppressed, plasma aldosterone concentration, that persisted normal, and a 24-h urinary aldosterone excretion rate, which was clearly high, supporting the suspected diagnosis. After the adrenalectomy, the patient remained asymptomatic with normal blood pressure without treatment and with normal serum potassium levels.

Pathophysiology, diagnosis, and treatment of mineralocorticoid disorders

The renin-angiotensin-aldosterone system (RAAS) is a major regulator of blood pressure control, fluid, and electrolyte balance in humans. Chronic activation of mineralocorticoid production leads to dysregulation of the cardiovascular system and to hypertension. The key mineralocorticoid is aldosterone. Hyperaldosteronism causes sodium and fluid retention in the kidney. Combined with the actions of angiotensin II, chronic elevation in aldosterone leads to detrimental effects in the vasculature, heart, and brain. The adverse effects of excess aldosterone are heavily dependent on increased dietary salt intake as has been demonstrated in animal models and in humans. Hypertension develops due to complex genetic influences combined with environmental factors. In the last two decades, primary aldosteronism has been found to occur in 5% to 13% of subjects with hypertension. In addition, patients with hyperaldosteronism have more end organ manifestations such as left ventricular hypertrophy and have significant cardiovascular complications including higher rates of heart failure and atrial fibrillation compared to similarly matched patients with essential hypertension. The pathophysiology, diagnosis, and treatment of primary aldosteronism will be extensively reviewed. There are many pitfalls in the diagnosis and confirmation of the disorder that will be discussed. Other rare forms of hyper- and hypo-aldosteronism and unusual disorders of hypertension will also be reviewed in this article.

The molecular basis of primary aldosteronism: from chimeric gene to channelopathy

Primary aldosteronism (PA) is the most common endocrine cause of high blood pressure. Only a minority of the PA cases are familial and due to known (CYP11B2/CYP11B1 chimeric gene or mutations in the KCNJ5 gene) or unknown causes. In the most common sporadic cases the mechanisms by which the excess aldosterone production persists in spite of high blood pressure, sodium retention, suppression of the renin angiotensin system and low potassium levels, all factors that by themselves would be expected to shut off aldosterone production, were a puzzle for decades. Only recently the discovery of functional mutations and down-regulation of potassium channels provided some explanations. We herein reviewed these recent findings and their mechanistic implications. We also propose a clinical molecular classification of familial hyperaldosteronism, which can be important from the practical standpoint as it considers besides the molecular features also the responsiveness to treatment and the imaging features.

Genetic spectrum and clinical correlates of somatic mutations in aldosterone-producing adenoma

Primary aldosteronism is the most common form of secondary hypertension. Somatic mutations in KCNJ5, ATP1A1, ATP2B3, and CACNA1D have been described in aldosterone-producing adenomas (APAs). Our aim was to investigate the prevalence of somatic mutations in these genes in unselected patients with APA (n=474), collected through the European Network for the Study of Adrenal Tumors. Correlations with clinical and biochemical parameters were first analyzed in a subset of 199 patients from a single center and then replicated in 2 additional centers. Somatic heterozygous KCNJ5 mutations were present in 38% (180/474) of APAs, whereas ATP1A1 mutations were found in 5.3% (25/474) and ATP2B3 mutations in 1.7% (8/474) of APAs. Previously reported somatic CACNA1D mutations as well as 10 novel CACNA1D mutations were identified in 44 of 474 (9.3%) APAs. There was no difference in the cellular composition of APAs or in CYP11B2, CYP11B1, KCNJ5, CACNA1D, or ATP1A1 gene expression in APAs across genotypes. Patients with KCNJ5 mutations were more frequently female, diagnosed younger, and with higher minimal plasma potassium concentrations compared with CACNA1D mutation carriers or noncarriers. CACNA1D mutations were associated with smaller adenomas. These associations were largely dependent on the population structure of the different centers. In conclusion, recurrent somatic mutations were identified in 54% of APAs. Young women with APAs are more likely to be KCNJ5 mutation carriers; identification of specific characteristics or surrogate biomarkers of mutation status may lead to targeted treatment options.

Predictors of successful outcome after adrenalectomy for primary aldosteronism

The underlying cause of resistant hypertension after adrenalectomy for primary hyperaldosteronism remains controversial. The objective of this study was to identify preoperative factors predictive of resistant hypertension in patients after undergoing retroperitoneoscopic adrenalectomy. Between 2003 and 2009, 124 patients with unilateral aldosterone-producing adenoma or unilateral adrenal hyperplasia underwent retroperitoneoscopic adrenalectomy at our institution. Clinical and biochemical data were reviewed retrospectively at baseline and after a median follow-up time of 59.2 ± 37.2 months. Adrenalectomy cured hypertension in 68 patients (54.8%) and 43 (34.8%) had persistent hypertension that was much easier to control after surgery, whereas 13 patients (10.4%) had continued hypertension and poor blood pressure control. Multivariate regression analysis revealed that the main determinants of postoperative cure were duration of hypertension less than 5 years [odds ratio (OR): 6.515, 95% confidence interval (CI) 2.278-10.293), number of antihypertensive medications ≤2 (OR: 2.939, 95% CI 1.254-5.235), preoperative response to spironolactone (OR: 3.405, 95% CI 1.681-6.985), the TT genotype of the CYP11B2 gene (344 C/T) (OR: 2.765, 95% CI 1.221-4.986), and the presence of adenoma rather than hyperplasia (OR: 5.274, 95% CI 2.150-8.141). The main determinants of surgical cure or control of hypertension in patients with primary hyperaldosteronism were duration of hypertension, number of antihypertensive medications, preoperative response to spironolactone, the presence of adenoma, and CYP11B2 (344 C/T) genotype. Consideration of these factors may help in the evaluation of patients for surgery and for the identification of patients with continued postoperative hypertension that may require more long-term monitoring and treatment.

An expert consensus statement on use of adrenal vein sampling for the subtyping of primary aldosteronism

Adrenal venous sampling is recommended by current guidelines to identify surgically curable causes of hyperaldosteronism but remains markedly underused. Key factors contributing to the poor use of adrenal venous sampling include the prevailing perceptions that it is a technically challenging procedure, difficult to interpret, and can be complicated by adrenal vein rupture. In addition, the lack of uniformly accepted standards for the performance of adrenal venous sampling contributes to its limited use. Hence, an international panel of experts working at major referral centers was assembled to provide updated advice on how to perform and interpret adrenal venous sampling. To this end, they were asked to use the PICO (Patient or Problem, Intervention, Control or comparison, Outcome) strategy to gather relevant information from the literature and to rely on their own experience. The level of evidence/recommendation was provided according to American Heart Association gradings whenever possible. A consensus was reached on several key issues, including the selection and preparation of the patients for adrenal venous sampling, the procedure for its optimal performance, and the interpretation of its results for diagnostic purposes even in the most challenging cases.

Long-term control of arterial hypertension and regression of left ventricular hypertrophy with treatment of primary aldosteronism

Primary aldosteronism (PA), a common cause of high blood pressure (BP), induces left ventricular (LV) hypertrophy and an excess rate of cardiovascular events. Whether its treatment provides long-term cure of hypertension and regression of cardiovascular damage remains uncertain. To the aim of assessing the effect of treatment of PA on BP and LV changes, we prospectively recruited 323 patients in a long-term follow-up study entailing serial echocardiography evaluations. Of them, 180 had PA and were assigned to either adrenalectomy (n=110) or medical therapy (n=70) on the basis of the adrenal vein sampling. The remaining 143 were consecutive optimally treated primary hypertensive patients. At baseline, the PA patients had more inappropriate LV mass than PH patients (27.1% versus 16.2%; P=0.020), despite similar BP values. At a median follow-up of 36 months (range, 6-225), BP was lowered (P<0.0001 versus baseline) to similar values in adrenalectomized (135±15/83±9 mm Hg), medically treated PA (133±11/83±7 mm Hg), and PH (139±15/86±9 mm Hg) patients. To this end, the adrenalectomized patients required significantly less drugs than the other groups. In PA patients, the LV mass index and the rate of LV hypertrophy fell through LV inward remodeling to the level of optimally treated PH patients, indicating that the LV work markedly decreased. Findings were similar when long-term (≥5 and ≥10 years) data were examined. Thus, an early diagnosis and a specific treatment of PA warrant normalization of BP and reversal of detrimental LV changes at long term.

Primary aldosteronism: comparison between guidelines of the Japanese and the US Endocrine Society

The US and Japanese Endocrine Societies recently both developed a therapeutic guideline for primary aldosteronism (PA). These guidelines indicate that differential diagnosis between PA caused by aldosterone-producing adenoma (APA) and bilateral adrenal hyperplasia (or idiopathic hyperaldosteronism [IHA]) is important and critical for treatment choice, while they show some inconsistency due to different frequencies of disorders and medical circumstances in respective countries. Japanese Endocrine Society guidelines have a unique description on the adrenal vein sampling (AVS) against microAPA, detection of which is difficult with current imaging tools and thus is frequently misdiagnosed as IHA. We reported that AVS performed in combination with adrenocorticotropic hormone stimulation was useful for diagnosing laterality of PA lesions, and APA underlay 74% of our cases with significant reduction of IHA compared with those previously reported. Laterality of PA should be precisely evaluated with AVS and imaging studies, as the results strongly influence the choice of therapeutic strategies.

Comprehensive re-sequencing of adrenal aldosterone producing lesions reveal three somatic mutations near the KCNJ5 potassium channel selectivity filter

Background

Aldosterone producing lesions are a common cause of hypertension, but genetic alterations for tumorigenesis have been unclear. Recently, either of two recurrent somatic missense mutations (G151R or L168R) was found in the potassium channel KCNJ5 gene in aldosterone producing adenomas. These mutations alter the channel selectivity filter and result in Na⁺ conductance and cell depolarization, stimulating aldosterone production and cell proliferation. Because a similar mutation occurs in a Mendelian form of primary aldosteronism, these mutations appear to be sufficient for cell proliferation and aldosterone production. The prevalence and spectrum of KCNJ5 mutations in different entities of adrenocortical lesions remain to be defined.

Materials and Methods

The coding region and flanking intronic segments of KCNJ5 were subjected to Sanger DNA sequencing in 351 aldosterone producing lesions, from patients with primary aldosteronism and 130 other adrenocortical lesions. The specimens had been collected from 10 different worldwide referral centers.

Results

G151R or L168R somatic mutations were identified in 47% of aldosterone producing adenomas, each with similar frequency. A previously unreported somatic mutation near the selectivity filter, E145Q, was observed twice. Somatic G151R or L168R mutations were also found in 40% of aldosterone producing adenomas associated with marked hyperplasia, but not in specimens with merely unilateral hyperplasia. Mutations were absent in 130 non-aldosterone secreting lesions.

KCNJ5 mutations were overrepresented in aldosterone producing adenomas from female compared to male patients (63 vs. 24%). Males with KCNJ5 mutations were significantly younger than those without (45 vs. 54, respectively; p<0.005) and their APAs with KCNJ5 mutations were larger than those without (27.1 mm vs. 17.1 mm; p<0.005).

Discussion

Either of two somatic KCNJ5 mutations are highly prevalent and specific for aldosterone producing lesions. These findings provide new insight into the pathogenesis of primary aldosteronism.

Polymorphic variation of CYP11B2 predicts postoperative resolution of hypertension in patients undergoing adrenalectomy for aldosterone-producing adenomas

OBJECTIVES

The surgical cure rate of patients with aldosterone-producing adenoma varies widely, and causes of persistent hypertension are not completely established. The objective of this study was to assess the blood pressure outcome in patients after retroperitoneoscopic adrenalectomy, and to analyze the CYP11B2 344 C/T polymorphism and any factors associated with the outcome.

METHODS

Between 2002 and 2009, 82 patients with unilateral aldosterone-producing adenoma underwent retroperitoneoscopic adrenalectomy. Clinical and biochemical data were reviewed retrospectively. Patients were investigated to assess the association of the CYP11B2 344 C/T polymorphism with resistant hypertension after surgery.

RESULTS

Adrenalectomy cured hypertension in 44 patients (53.7%), and 27 patients (32.9%) had persistent hypertension that was much easier to control after surgery, whereas 11 patients (13.4%) had continued hypertension and poor blood pressure control. Multivariate regression analysis showed that the main determinants of postoperative cure were duration of hypertension less than 5 years (OR 4.515, 95% CI 1.978-10.293), number of antihypertensive medications ≤2 (OR 2.639, 95% CI 1.154-6.035), preoperative response to spironolactone (OR 3.105, 95% CI 1.381-6.985) and the TT genotype of the CYP11B2 gene (344 C/T; OR 2.765, 95% CI 1.261-6.064).

CONCLUSIONS

The 344 C/T polymorphism of the CYP11B2 gene predicts resolution of hypertension in patients undergoing adrnelactomy for aldosterone-producing adenoma. Duration of hypertension, number of antihypertensive medications, and preoperative response to spironolactone also represents predictive factors that need to be considered for the identification of patients with continued postoperative hypertension requiring long-term monitoring and treatment.

Prevalence, Clinical, and Molecular Correlates of KCNJ5 Mutations in Primary Aldosteronism

Primary aldosteronism is the most common form of secondary hypertension. Mutations in the KCNJ5 gene have been described recently in aldosterone-producing adenomas (APAs). The aim of this study was to investigate the prevalence of KCNJ5 mutations in unselected patients with primary aldosteronism and their clinical, biological and molecular correlates. KCNJ5 sequencing was performed on somatic (APA, n=380) and peripheral (APA, n=344; bilateral adrenal hyperplasia, n=174) DNA of patients with primary aldosteronism, collected through the European Network for the Study of Adrenal Tumors. Transcriptome analysis was performed in 102 tumors. Somatic KCNJ5 mutations (p.Gly151Arg or p.Leu168Arg) were found in 34% (129 of 380) of APA. They were significantly more prevalent in females (49%) than males (19%; P <10 −3 ) and in younger patients (42.1±1.0 versus 47.6±0.7 years; P <10 −3 ) and were associated with higher preoperative aldosterone levels (455±26 versus 376±17 ng/L; P =0.012) but not with therapeutic outcome after surgery. Germline KCNJ5 mutations were found neither in patients with APA nor those with bilateral adrenal hyperplasia. Somatic KCNJ5 mutations were specific for APA, because they were not identified in 25 peritumoral adrenal tissues or 16 cortisol-producing adenomas. Hierarchical clustering of transcriptome profiles showed that APAs with p.Gly151Arg or p.Leu168Arg mutations were indistinguishable from tumors without KCNJ5 mutations. In conclusion, although a large proportion of sporadic APAs harbors somatic KCNJ5 mutations, germline mutations are not similarly causative for bilateral adrenal hyperplasia. KCNJ5 mutation carriers are more likely to be females; younger age and higher aldosterone levels at diagnosis suggest that KCNJ5 mutations may be associated with a more florid phenotype of primary aldosteronism.